Method of manufacturing cold-drawn metallic articles



(No Model.) 2 Sheets-S l 1-eet 1.

W. A. MoGOOL.

METHOD OF MANUFACTURING GOLD DRAWN METALLIC ARTICLES.

No. 602,417. Patented Apr. 12, 1898.

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(No Model.)

2 SheetsSheet 2 'W. MoCOOL. METHOD OF MANUFACTURING GOLD DRAWN METALLICART'IGLES. No. 60 2,417.

Patented Apr. 12, 1898.

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\VILLIAM A. MCCOOL, OF BEAVER FALLS, PENNSYLVANIA.

METHOD OF MANUFACTURING COLD-DRAWN METALLIC ARTICLES.

SPECIFICATION forming part of Letters Patent No. 602,417, dated April12, 1898.

Application filed October 24, 1896. Renewed March 24,1898, berial No.675,039. (No specimens.)

To all whom, it may concern:

Be it known that LWILLIAM A. McCooL, a citizen of the UnitedStates,residing at Beaver Falls, in the county of Beaver and State ofPennsylvania, have invented certain new and useful Improvements inMethods of Manufacturing Cold-Drawn Metallic Articles, (for all or partsof which there have been issued to me Letters Patent in the Kingdom ofGreat Britain and Ireland, No. 25,686, dated November 14,1896; inFrance, No. 270,462, dated September 14, 1897, and in the Kingdom ofBelgium, No.130,827, dated September 24, 1897;) and I do declare thefollowing to be a full, clear, and exact description of the invention,such as will enable others skilled in the art to which it appertains tomake and use the same, reference being had to the accompanying drawings,and to the letters and figures of reference marked thereon, which form apart of this specification.

Heretofore in manufacturing cold-drawn tubing it has been customary toemploy bil lets of specially-prepared steel, which are first perforatedaxially by drilling or other suitable means and afterward have thecentral opening enlarged to the desired diameter, the billets beingelongated bypassing them while heated over mandrels of-difierentdiameters. After that they are cleaned of scale by the action of acid,limed, and annealed and are then ready for drawing.

One of the objects of the present invention is to obviate the expenseincident to this method of manufacture heretofore followed.

Another purpose is to avoid the deleterious effect wrought upon themetal by the acid or basic materials heretofore used in cleaning thetubes.

By following my process even lap-welded or butt-welded tubing can beemployed, such as is cheaply manufactured for various purposes.

To remove the scale (consisting of oxids' and other materials) either atone of the initial steps of my manufacture or at the later stages, Isubject the surface of the metal to mechanical abrasion incontradistinction from chemical treatment. This abrasion may beaccomplished in any of several ways. At

present I prefer to expose the metal surfaces to the action of a blast,such as a blast of air, carrying small particles of hard abradingmaterial. Numerous materials consisting of masses of small particlessuitable for this purposev are well known; but I have found that thebest results are obtained when use is made of small particles ofrelatively hard metal, such as small shot or metallic globules, theybeing preferable to emery, sand, or non-metallic particles in this thatthey are not liable to adhere to or remain upon the surface of themetal, and if any of them should so adhere they will not cut or mar themandrel or diesused in the steps of drawing. When a blast carryingsuitable materials of this class is properly applied, it can byitssimple mechanical abrasive action be caused to remove all scale andother excessively hard substances foreign to the pure metal desired andwhich are liable to mar the drawing dies or mandrels and also to leaveimperfections in the tube, and this abrading can, if desired, beaccomplished in such way as to form numerous more or less minuteindentations on the surface of the metal, the result of such pittingbeing to assist the flow of metal when being drawn, minute spaces beingprovided adjacent to the contact-points of the dies and into which thefibers or molecules of the metal can pass under the pressure; but thismay be regarded as independent of the cleaning or scale-removing effectof the abrasion. This mechanical abrasion can be applied as frequentlyas is desired during the entire process of forming the tube, it beinggenerally desirable to apply it after each annealing or heating.

\Vhen my process is employed in the manufacture of drawn tubing fromthose initial tubes or blanks which are formed by bending up fiat platesand lap-welding or buttwelding the edges, it is desirable sometimes tonot only treat them in the Way above described, but also to remove thesurplus metal that appears along the line of union of the welded edges,and thereby produce a thickness of metal which is uniform incross-section on all radial lines, and this I accomplish by cutting awaysuch surplus metal on lines longitudinal of the tube. This can be doneat an earlier or a later stage in the drawing of the finished tube; butgenerally I prefer to take this step, when necessary, at an earlystageto wit, after the initial cleansing of the interior surface.

I have also found that when tubing is being drawn on the bench it isvery desirable to apply the longitudinal propelling force to the tube bymechanism capable of more or less yielding, so that the propulsion shallnot be absolutely positive and fixed at all times, but

. such as to allow slight checks in the advance,

the result being to permit the metal to more gradually flow at thoseinstants when extraordinary resistance is experienced. For this purposea frictional engagement of two of the driving or propelling devices isadvantageousas, for instance, by employing a driving-drum with a chainor cable wrapped around it.

Another matter of importance is to have the tube-propellin g mechanismcomprise two parts which can be brought into engagement at anytransverse lineas, for instance, by having a cable or chain of uniformcross-section throughout its entire length and a gripper adapted to bequickly connected thereto at any point. This is in contradistinctionfrom the plan commonly followed of drawing the tube by means of a hookor pin and a chain which can only engage with the hook at certain pointsseparated by relatively large ntervals.

In the drawings 1 have illustrated toolsand machines of some sorts whichcan be used in carrying out my process.

Figure 1 is a section of a drawing-bench. Fig. 2 is a side elevation ofone form of appa ratus adapted for mechanically abrading the exteriorsurface of a tubular blank in accordance with my invention. Fig. 3 is aView of a device adapted to apply the abrading ma terial to the interiorof the blank. Fig. 4: is a view of a slightly-modified device forapplyin g the blast to the interior of the blank. Fig. 5 is a view, onan enlarged scale, of the exterior surface of the blank after havingbeen subjected to the action of the mechanism shown in Fig. 3. Fig. 6 isa sectional view of the tool for removing surplus metal from theinterior of the blank.

In, the description below I will assume for the sake of simplicity thatit is desired to manufacture fine cold-drawn tubing from initial blanksproduced by lap-welding or butt-welding, it being understood, however,that some of the matters to be described are also applicable to themanufacture of tubes from solid billets. As generally I subject theblanks to the action of the drawing bench or machine at an earlystage, Iwill refer briefly to that mechanism first.

1 1 designate the side rails of the bed or support of they apparatus,which rails are mounted at their ends upon suitable'pedestalsorstandards 2 2.

12 designates a stationary circular die rigidly secured to the side bars1 1 at an intermediate point of their length. This die maybe constructedin any preferred and wellknown manner.

In ways or guides X, formed on the inner faces of the side bars 1, arefitted carriages 9 9, by which the tube is moved longitudinally of thebed through the circular die 12, each of these carriages being providedwith adjustable jaws or clamps for grasping the tube or blank D.

50 designates an endless rope or cable which passes around a suitabledriving-drum 51 and guide Wheelsor drums 52, journaled in the pedestalsor standards 2. Each carriage 9 9 is provided with means for attachmentto said endless rope or cable, whereby such carriage and the tube D whenengaged by said carriage may be moved longitudinally of the bed and thetube forced through the die 12.

The cable-grippin g jaws of the carriage are arranged on opposite sidesof the'path of the cable 50 and adapted to be moved by a handlever orcrank-handle 21 inwardly to grip said cable or outwardly to release thesame. The handle 21 can be secured in position by any suitable means. Bymoving said handles the carriages 9 9, or either of them, can beinstantly connected with or disengaged and released from the cable.

4: designates the mandrel, which is supported from the bed at one endand may be of any suitable style and construction. Preferably it issupported in a tailpiece 5 and connected with an adj usting-screw 6. Forholding the mandrel in a straight line throughout its length I employ aseries of auxiliary supports or holders. Each of these movable holderscomprises a vertical shaft 17, mounted in a bearing projected laterallyfrom the side or bed rails 1. Each shaft 17 is provided at its upper endwith an armS, which normally extends inwardly over the bed-frame andengages with the mandrel 4. The vertical shaft 17 is normally held insuch position as to cause the arm 8 thereof to contact with the mandrelby means of a coiled spring 15, fitted around the lower portion of saidshaft.

To support and guide the tube as it moves toward the compressing-die at12, I employ a guide-stand 30, bolted to the frame-bars 1 1.

The mechanism above described is used as follows: The die 12 is properlyplaced and the mandrel is adjusted so that its head leis in properposition relative to the die. If the tube is to be compressed from theexterior only, the mandrel can be temporarily withdrawn, and vice versa.When the parts are in position, a tube D is pushed forward, and itsfront end is passed to a point somewhat in front of the carriage 9, thelatter being at this time disengaged from the cable 50. When the tube isproperly placed, the parts are so adjusted as to cause the tube-engagingjaws of the carriage to tightly grip the tube, and then the lever 21 ismoved to cause the cablegripping jaws to engage the cable. As soonas thecarriage 9 is thus caught by the cable the latter forces it and the tubetoward the die 12, the tube projecting a short distance in front of thecarriage. The propelling of the tube continues until its forward end haspassed through the die far enough to permit it to be connected to thecarriage 9. Then the carriage 9 is released from the cableand from thetube. After this the carriage 9 is clamped to the tube and connected tothe cable. After the occurrence of the latter the carriage 9 commencesto move with the cable and to draw the tube through the die.

If an interior mandrel is in use, its stem 4 is supported in alinement,as aforesaid, by the movable arms 8. If at any time it is desired toobtain a new grip upon the tube at points farther back from its forwardend, the carriage 9 is released from the cable and from the tube andpushed by hand or otherwise backward to a position near the die, afterwhich it is again clamped to them and the drawing continued. Should itbe desired to propel the tube from both sides of the die that is, toimpart both a pushing and a pulling action-both carriages can be clampedto the cable and the tube.

I have above briefly described and in Fig. 1 of the drawings haveillustrated, more or less conventionally, the form of draw-bench which Iat present prefer, the same being particularly described and illustratedin my application for patent, Serial No. 605,657, to which reference maybe had for the details of construction; but it will be understood thatother forms of drawing mechanism may be substituted for that selectedfor purposes of illustration herein without departing from my presentinvention.

It will be understood that to the mechanism above described the tube issubjected as often as necessary to reduce it to the desired thinness andto bring it to the required diameter and also understood that atsuitable intervals between successive drawings in that machine it issubjected to the action of other tools or mechanisms when necessary, asfor the purpose of cleansing, for removing surplus metal, annealing,the. For cleansing it by mechanical abrasion, as above described, asimple mechanism can be used. In Figs. 2, 3, and 4 I have illustrated amechanism adapted to carry out this step in my process, referring towhich A designates an air-compressor, with which is connected areceptacle B for containing the shot or other abrasive material, saidreceptacle having a delivery-spout 6 arranged at the axis of thedelivery-tube a of the compressor A. \Vith the latter is connected aflexible pipe 0, terminating in a nozzle '0. The tube D is supported ona spindle 61, mounted in a suitable casing E. Said spindle is adapted tobe rotated by means of a pinion d, with which meshes a gear (1 connectedwith a crank (Z The nozzle 0 is adapted to be fitted to a holder e,fitted in suitable guides to move longitudinally of the casing E, sothat the blast of air carrying the abrasive material can be applied tothe entire exterior surface of the tube D.

WVhether the devices just described or others be used for holding themetal while applying the blast the latter must be applied in such way asto similarly impinge upon each and every part of the surface, so thatthere shall be a uniform cleansing along all longitudinal lines and atall points. This can be readily accomplished in the way described byrotating the tube while the blast is being applied, so that the streamof shot will at one instant or another impinge upon every point or smallarea of the article and act uniformly throughout the entire surface.Such a treatment is superior to that attained by merely passing thearticle longitudinally past a fixed blast-nozzle or even passing thenozzle rectilinearly along one longitudinal line, for in such case therewould be regions of abrasion and also lines where practically noabrasion occurs, with the resulting danger that small particles of thescale would be left adhering to the surface, any one of which would marand possibly ruin the die. Hence I insure a uniform action of the blastupon all parts of the surface, not only to insure the entire removal ofevery particle of scale, but also provide against cutting away the steelmore at one place than at another.

In order to apply the blast to the interior of the tube D, either of thedevices illustrated .in Fig. 3 or Fig. 4 may beemployed.

similar to that at e. The door 6 at the rear of the casing is opened,and the other end of the tube D is supported in a tubular holder f,carried by a casing F, similar to that at E; or, if desired, a nozzlesimilar to that shown in Fig. 4 may be employed. In this style thenozzle 8 is of such form and size as to pass into the tube D, and itsmovements are controlled by or through the flexible supply-pipe O. Thescale upon the interior is often very refractory, and in order to havethe blast exert the most efficiency it is better, prior to applying thelatter, to pass the tube through properly-sized external dies, whichwill act to slightly compress it and by such compression crack or loosenthe scale on the interior, and after such loosening by compression theabrading devices are able to entirely remove it and leave a clean andpolished interior. The effect of the blast of abrading material upon thetube is to remove the scale therefrom and also form numerous minuteindentations or pits in the surface of the metal, as indicated at a inFig. 5. This treatment by abrasion is advantageously applied after anystepliable to produce scale, oxid, or the like as, for instance, anintermediate annealing and as concerns this feature of the invention I11the first the nozzle 0 is inserted into a holderit will be seen that itis applicable. to drawn tubes whatsoever be the nature of the initialblanks, even those provided by perforating a solid billet; but, as abovesaid, one of my purposes is to provide a method of treatment which shallalso be applicable to tubes formed from blanks or initial tubes whichare formed from plates with lap-welded or butt-welded edges. Tubes ofthis latter sort, owing to inaccuracy in the mechanism by which they areformed and owing to' the nature of the union of the edges, have one ormore longitudinal lines along which the metal is relatively thickened,the thicken ed part often amounting to a rib-like projection extendinginward on the interior of the tube, and even tubes or blanks formed byperforating solid billets are often found to contain lines of metalwhich it is desirable to remove at an earlier or a later stage in thedrawing. To remove such an inwardprojecting part of the metal or to forany purpose effect a longitudinal out, I prefer to employ an implementof the form illustrated and described in detail in my application SerialNo. 605,656 and generally illustrated in Fig. 6 herein. It consists of abody G, adaptedto be attached to a mandrel H and provided with a cuttingedge g and a passage g, through which the cuttings produced by thecutter can pass to a point in rear of the body of the implement.

Having thus described some of the devices at present preferred forcarrying out my improvements, I now call attention to the ways in whichthey can be used.

For instance, I can either commence with blank tubes obtained from othermanufacturers and made by the butt-welding or lapwelding process or canmyself provide such blanks by heating flat sheets, bending them insuitable machinery, bringing together the side edges of each sheet,causing more or less of the metal along each edge to overlap that of theother and welding the edges, and there is generally more or less metalleft as a surplus along the line of the weld, causing a variance from auniform cross-section of the tube, or I can employ initialblanks,produced by perforating billets. In either case there are stagesin the manufacture when heating is necessary or subjecting to sometreatment which produces scale or foreign undesirable material thattends to cut or mar the dies or mandrels.

Let it be assumed that the lap-welded tubes are used and that I desireto reduce, for example, a large lap-welded tube (say one two inches indiameter) to a very thin walled tube of small diameter, (say one-halfinch in diameter.) My invention provides for taking the following steps,among others, to wit: I first subject the blank to a cleansing of theexterior surface, preferably by submitting it to the aforesaid blast ofair carrying particles of abrading material, though for the exteriorsurface, under some circumstances, as when the metal is sufficientlythick, other modes of cleansing can be followed, for the texture of themetal is not at such times dangerously attacked to any particular depthby the reagent. Then after cleansing the exterior the tube can beintroduced into a drawing-bench, (such as in Figs. 1 and 2,) theexternal die only being present, the interior mandrel being. removed,and after one or two passes the metal will be compressed sufficiently tocrack or loosen the scale on the interior surface. After that theinterior is subjected to the action of abrading material, and if this bea stream of small metallic particles, like minute chilled shot, the saidsurface will be thoroughly cleaned and nothing left therein of suchcharacter as to scratch or mar the dies or mandrel. This being done, itis advisable to now apply the cutting-tool (such as shown in Figs. 9 and10) to remove surplus metal along the line of the weld and reduce thetube to a uniform thickness in cross-section. Ordinarily it will now beready to go through a series of passes on the drawing-bench, theexternal die and the interior mandrel being so sized and related (forthe purpose at present assumed) as to gradually both reduce the diameterof the tube and also reduce the thickness of its walls. During thesesteps of drawing it will often be found that a reheating of the metal isadvisable. Such heating at once makes liable the production of newscale, oxid, &c. When this occurs, return must be had to the air-blastand abrading material. If the acid or basic treatment commonly employedbe applied, the purity in the texture of the metal is attacked,particularly as the thinness increases, and yet all of the scale must beremoved lest a remaining particle should, by reason of its extremehardness, be crowded into the softer metal, and thereby create a seriousflaw or cut into the smooth and polished surface of the die or mandrel,and thereby introduce a possible factor of destroying the whole article.Moreover, a serious difficulty, as is well known, is experienced almosteverywhere in using the finished tubes, (as well as shafts orbars whichhave been subjected to acid treatment,) because of the fact that thesearticles refuse to receive and retain upon their surfaces othermaterials that may be applied-such as enamel, japan, and platings. Thishas been found to be due to the effects of the acid. Even the highestgrades of cold-drawn tubing-such as are used in the manufacture ofbicycles, for instanc'eare found to present upon their surfaces numerouspits or holes into which the acid has eaten its way, and the entiresurface is more or less characterized by the presence of acid or itscompounds, such as sulfate of iron. The bicycle manufacturer has tosubject this tubing, after he has purchased it from the tubemanufacturer, to a grinding and polishing action in order to cut thesurface down to the bottom of these acidcavities. In other words, he hasto reduce the surface far enough to reach a wide surface of pure metalbefore he can apply the enamel, japan, or other surfacing material;otherwise the latter would peel off or flake off, as is well known tomanufacturers. Even then it is no uncommon occurrence to have thischemical action of the acid continue after enameling or japanning untilthe metal is eaten through or weakened to the point of breakage. Allthis is obviated by following the method which I have devised. The metalarticles pass from my hands to the other manufacturer in such a purestate that the surfaces that require enameling or japanning can besuccessfully and permanently coated immediately without furthertreatment. The acid materials (used at one stage or another in thedrawing process for cleaning such articles) accomplish their work byattacking the pure metal and eating under the specks or flakes of scaleor silicate compound, whereas in the present process these foreignmaterials are directly attacked by the shot-blast and removed, leavingall the pure metal.

I am aware that glass has been out and that metal surfaces have beentreated by means of sand-blasts, but I believe myself to have discoveredthat such a treatment of metal as I have described can be employed as animportant adjunct in the cold drawing of it, in that I can thereby giveto the external or interior dies or mandrels surfaces of pure metal toact upon-that is, surfaces not only free from the scale formed inearlier stages 'of treating the metal and that formed during the processof cold-drawing, but also free from acid and acid compounds.

As above stated, I prefer to use for the cleansing agent masses of veryminute spherical metallic shot in contradistinction from masses ofparticles having angular surfaces. Sand and similar materials can besuccessfully used, provided that great care is taken to subsequentlyclean such material off from every part of the surface and alsorepeatedly cleanse the surfaces of the dies and of the mandrels. Suchmaterials as sand and the like have more or less angular surfaces andtherefore there is a tendency for them to adhere to the smooth metallicsurfaces ofthe dies and of the tubes or bars, and if any should thusadhere, even though very minute, they would result in a cutting not onlyof the tubing, but of the drawing implements, for, as is well known, thevery dust itself of such bodies results frequently in great loss. Theglobular metallic particles which I employ are superior, because oftheir lacking entirely the tendency to adhere to metallic surfaces. Whenpropelled in a stream with great force, they cut the scale rapidly andthoroughly and then instantly disengage themselves from the metalsurfaces, so that neither the mandrels nor the dies are harmed.

It will be readily seen that many of the features of improvement arejust as applicable in treating tubes which commence initially asperforated billets, for it is just as necessary with them to effect acleansing at one stage or another, and under some circumstances it isdesirable to cut or similarly remove from them certain lines orprojections of metal which prevent the production of the desired uniformtubing.

WVhat I claim is 1. The herein-described method of treating blanks forthe manufacture of drawn tubing, it consisting in abrading the exteriorsurface of the blank, then compressing the blank radially, then abradingthe interior surface of the blank, and then subjecting the blank to theaction of the draw-bench, substantially as set forth.

2. The herein-described improvement in the manufacture of drawn tubing,it consisting in drawing a tubular blank through a die and compressingthe metal of the blank radially, abrading the interior surface of theblank, and then drawing the blank over a mandrel or through a die,substantially as set forth.

3. The herein-described improvement in the method of manufacturing drawntubing, it consistingin drawing a tubular blank through a die tocompress the metal radially, then abrading the interior of the blank,then drawing the blank over a mandrel or through a die, then heating theblank, and then again abrading the blank to remove any scale that hasformed thereon, substantially as set forth.

4. The herein-described improvement in the method of manufacturing drawntubing, it consisting in abradin g the exterior surface of a tubularblank, then drawing said blank through a die to compress the metalradially, then abrading the interior surface of the blank, then drawingthe blank overa mandrel or through a die, and then heating the blank,substantially as set forth.

5. The herein-described improvement in the method of treating metallicblanks in drawing, it consisting in rotating the blank and whilerotating exposing it to a stream of minute globular metallic shot,whereby its surface is uniformly cleaned in contradistinction fromsubjecting them to the action of acid or other chemical reagents, toremove scale and expose a surface of the pure metal, and then subjectingthe blank to compression radially along the cleaned surface to elongateand condense the fibers, substantially as set forth.

6. The herein-described method of manufacturing blanks for drawn tubingfrom lapwelded or butt-welded tubes, it consisting in removing scalefrom the exterior of the tube, then compressing the blank radially toloosen the interior scale, then removing said interior scale, and thenreducing the walls of the tube to uniform thickness by removing surplusmetal on lines longitudinally surface of the tube on lines longitudinalof of the blank, substantially as set forth. the tube, substantially asset forth. 1o 7. The herein-described method of prepar- In testimonywhereof I aifix my signature ing blanks for the manufacture of drawn inpresence of two witnesses. 5 tubing from lap-Welded or butt-weldedtubes, WILLIAM A. MOCOOL.

it consisting in abrading the exterior of the W'itnesses: tube, abradingthe interior of the tube, and JOHN WV. OULMER,

then removing surplus metal from the inner JAMES F. MERRIMAN.

